Tensions between China and Japan over wartime history took on a new dimension after Chinese authorities impounded a ship owned by Japan's Mitsui O.S.K. Lines Ltd. over a legal dispute dating back to the 1930s.

The Shanghai Maritime Court ordered the seizure on Saturday of the Baosteel Emotion—an iron-ore carrier—at a port in the eastern Chinese province of Zhejiang, according to statements on the websites of the court and Mitsui.